1. Field of the Invention
The present invention relates to elastic wave devices and methods for manufacturing the same, and in particular, relates to elastic wave devices including vibrating portions such as resonators and filters located on substrates and methods for manufacturing the same.
2. Description of the Related Art
To date, elastic wave devices including substrates, vibrating portions formed on the substrates, and cover layers covering the vibrating portions have been proposed.
FIGS. 9A to 9C illustrate an example configuration of an elastic wave device. FIG. 9A is a cross-sectional view, FIG. 9B is a cross-section taken along line X-X in FIG. 9A viewed from above, and FIG. 9C is a cross-section taken along line X-X in FIG. 9A viewed from below. As shown in FIGS. 9A to 9C, a surface acoustic wave device 110 includes a piezoelectric substrate 111, a conductive pattern including IDT electrodes 112, pads 113, and wiring lines 118 formed on a first main surface 111a of the piezoelectric substrate, a frame-shaped supporting layer 116 composed of resin formed so as to enclose a vibrating portion including the IDT electrodes 112, and a cover layer 115 formed of an insulating sheet formed on the supporting layer 116. External electrodes 117 are formed on the cover layer 115, and the external electrodes 117 and the pads 113 are electrically connected to each other by via conductors 114 extending through the cover layer 115 and the supporting layer 116 (for example, see Japanese Unexamined Patent Application Publication No. 2002-261582
When an elastic wave device having the above-described structure is mounted on, for example, another circuit board using solder bumps formed on the external electrodes, flux is applied to the solder bumps so as to improve the solder wettability. However, the flux often flows into a hollow space through the cover layer.